/*
 * Created on Jun 1, 2005 TODO To change the template for this generated file go to Window -
 * Preferences - Java - Code Style - Code Templates
 */

package org.owasp.webgoat.lessons;

import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.ecs.Element;
import org.apache.ecs.ElementContainer;
import org.apache.ecs.StringElement;
import org.apache.ecs.html.B;
import org.apache.ecs.html.Input;
import org.apache.ecs.html.P;
import org.apache.ecs.html.PRE;
import org.owasp.webgoat.session.ECSFactory;
import org.owasp.webgoat.session.WebSession;
import org.owasp.webgoat.util.HtmlEncoder;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.XMLReaderFactory;


/***************************************************************************************************
 * 
 * 
 * This file is part of WebGoat, an Open Web Application Security Project utility. For details,
 * please see http://www.owasp.org/
 * 
 * Copyright (c) 2002 - 2007 Bruce Mayhew
 * 
 * This program is free software; you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with this program; if
 * not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 * 
 * Getting Source ==============
 * 
 * Source for this application is maintained at code.google.com, a repository for free software
 * projects.
 * 
 * For details, please see http://code.google.com/p/webgoat/
 * 
 * @author rdawes
 * 
 *         TODO To change the template for this generated type comment go to Window - Preferences -
 *         Java - Code Style - Code Templates
 */
public class WsSAXInjection extends LessonAdapter
{

	private final static String PASSWORD = "password";

	private String password;

	private static String template1 = "<?xml version='1.0' encoding='UTF-8'?>\n" + "<wsns0:Envelope\n"
			+ "  xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'\n"
			+ "  xmlns:xsd='http://www.w3.org/2001/XMLSchema'\n"
			+ "  xmlns:wsns0='http://schemas.xmlsoap.org/soap/envelope/'\n"
			+ "  xmlns:wsns1='http://lessons.webgoat.owasp.org'>\n" + "  <wsns0:Body>\n"
			+ "    <wsns1:changePassword>\n" + "      <id xsi:type='xsd:int'>101</id>\n"
			+ "      <password xsi:type='xsd:string'>";

	private static String template2 = "</password>\n" + "    </wsns1:changePassword>\n" + "  </wsns0:Body>\n"
			+ "</wsns0:Envelope>";

	static boolean completed;

	protected Category getDefaultCategory()
	{
		return Category.WEB_SERVICES;
	}

	protected List<String> getHints(WebSession s)
	{
		List<String> hints = new ArrayList<String>();

		hints.add("The backend parses the XML received using a SAX parser.");
		hints.add("SAX parsers often don't care if an element is repeated.");
		hints.add("If there are repeated elements, the last one is the one that is effective");
		hints.add("Try injecting matching 'close' tags, and creating your own XML elements");

		return hints;
	}

	private final static Integer DEFAULT_RANKING = new Integer(150);

	protected Integer getDefaultRanking()
	{
		return DEFAULT_RANKING;
	}

	public String getTitle()
	{
		return "Web Service SAX Injection";
	}

	protected Element makeInputLine(WebSession s)
	{
		ElementContainer ec = new ElementContainer();

		ec.addElement(new P().addElement("Please change your password: "));

		Input input = new Input(Input.TEXT, PASSWORD);
		ec.addElement(input);

		Element b = ECSFactory.makeButton("Go!");
		ec.addElement(b);

		return ec;
	}

	protected Element createContent(WebSession s)
	{
		ElementContainer ec = new ElementContainer();
		try
		{
			ec.addElement(makeInputLine(s));

			password = s.getParser().getRawParameter(PASSWORD, null);

			PRE pre = new PRE();
			String xml = template1;
			xml = xml + (password == null ? "[password]" : password);
			xml = xml + template2;
			pre.addElement(HtmlEncoder.encode(xml));
			ec.addElement(pre);

			if (password != null)
			{
				ec.addElement(checkXML(s, xml));
			}
		} catch (Exception e)
		{
			s.setMessage("Error generating " + this.getClass().getName());
			e.printStackTrace();
		}
		return (ec);
	}

	private Element checkXML(WebSession s, String xml)
	{
		try
		{
			XMLReader reader = XMLReaderFactory.createXMLReader();
			PasswordChanger changer = new PasswordChanger();
			reader.setContentHandler(changer);
			reader.parse(new InputSource(new StringReader(xml)));
			if (!"101".equals(changer.getId()))
			{
				makeSuccess(s);
				return new B(HtmlEncoder.encode("You have changed the passsword for userid " + changer.getId()
						+ " to '" + changer.getPassword() + "'"));
			}
			else
			{
				return new StringElement("You changed the password for userid 101. Try again.");
			}
		} catch (SAXException saxe)
		{
			return new StringElement("The XML was not well formed: " + saxe.getLocalizedMessage());
		} catch (IOException ioe)
		{
			return new StringElement(ioe.getLocalizedMessage());
		}
	}

	private static class PasswordChanger extends DefaultHandler
	{

		private static String PASSWORD_TAG = "password";

		private static String ID_TAG = "id";

		private String id = null;

		private String password = null;

		private StringBuffer text = new StringBuffer();

		public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException
		{
			text.delete(0, text.length());
		}

		public void characters(char[] ch, int start, int length) throws SAXException
		{
			text.append(ch, start, length);
		}

		public void endElement(String uri, String localName, String qName) throws SAXException
		{
			if (localName.equals(ID_TAG)) id = text.toString();
			if (localName.equals(PASSWORD_TAG)) password = text.toString();
			text.delete(0, text.length());
		}

		public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException
		{
			text.append(ch, start, length);
		}

		public String getId()
		{
			return id;
		}

		public String getPassword()
		{
			return password;
		}

	}
}
